I was about to place a small order from All Electronics, a great miscellaneous parts and surplus electronics shop, when I checked the front page to see if there was anything new to consider. And that’s where I saw a familiar-looking LED worklight lamp head.

I recognized these as from Dewalt DCL040 LED flashlights ($49 via Amazon).

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Here’s their product description:

This good looking fixture is a great beginning for a shelf or display lighting project. Bright, white 1 Watt LED enclosed in a rugged black and yellow hard plastic housing with a conical reflector and a clear plastic front lens. Overall dimensions, 2.16″ diameter x 3.45″ long. Two 4″ wire leads. Operates on 3 Vdc @ 300 mA. For higher voltages use a dropping resistor (see image to left).

These are powered off of 3V (I tested one – it works), and you can use a higher voltage source if you choose an appropriate resistor. There’s a handy chart on the All Electronics website if you’re not familiar with powering LEDs and don’t want to head to Google for answers.

If I wanted to use a 5V power supply, I’d need a 6.67 Ohm resistance. I’d have an easier chance looking for a standard-valued 6.8 Ohm resistor. The power dissipated across the resistor will be 2V x 0.3A = 0.6W, so I’d need a 1W resistor. Or 3/4W, but I assume there’s greater selection of 1W resistors.

(I say I and not you because I’m just thinking aloud here. You’re on your own in determining a safe and reliable way to power these LED modules. I have only tested these lights at 3V, and briefly at that. I’ve got more work to do. Use any of this at your own risk.)

If I wanted to use a 6V power supply, I’d need a 10 Ohm resistance or slightly greater. Again, I’d need a 1W resistor. Maybe 12 Ohms?

1W resistors are fairly easy to find. A quick search on Mouser turned up a couple of options. 6.8 Ohm with 1W power rating and 5% tolerance sells for as low as 10 cents each, individually.

Maybe Amazon, Ebay, or a straight-from-China marketplace would be a good place to look for just a couple resistors. There’s also this Joe Knows Electronics 1W resistor kit for $35, but that’s overkill. I ordinarily use 1/4W or 1/2W resistors and would be hesitant to buy a 1W assortment for myself.

I order from Mouser regularly and will likely spend $10 on a few 1W resistors with my next order.

There are higher rated resistors too, obviously at higher cost.

But if using higher voltage supplies, maybe a voltage regulator is the way to go. Maybe I’d try for a 3.3V voltage regulator, perhaps with a small resistor to drop the voltage to 3V? A 0.3V drop at 0.3A would be what, 90 mW, so a 1/4W resistor would be more than enough.

Ben – your thoughts? How would you power these LEDs from a DC battery source?

I might dig up a fully assembled Dewalt LED flashlight and see what they use to drop the voltage from 20V Max (18V) to 3V.

I knew I wanted a couple, so what the heck, I ordered 10.

They’re a little dirty, with flecks of black (plastic?) stuck on, but they seem easy to clean. They feel a little greasy too. One wire has some fixturing epoxy stuck to it.

Anyone know what that white hot-glue-like fixturing stuff is called?

In other words, it seems that these were removed from assembled work lights. Some of the lenses are scratched a little, but aside from the slight amount of dirt, these look new.

So I’m going to assume they were removed from new equipment.

I’m not quite sure what I’ll do with 10 of them. Some will go to an LED worklight light bar project. Maybe I’ll swap the white LEDs in a few for RGB LEDs.

The output is quite center-concentrated. The deep reflector is a good one, but the output is a little harsh.

I definitely got my money’s worth, but I just have to now find a good way to use them.

Ideas?

At $2.50 each, who else is buying a few?

Oh, and if you do order one and take it apart, I’d appreciate any advice! The yellow housing screws together in one place, but I can’t see an easy way to remove the LED emitter, reflector, and lens assembly – the black part.

I wonder how and why these ended up at a surplus electronics parts store. Maybe something was off-spec. The LEDs? The housings? I doubt anyone at Dewalt will tell me, and All Electronics might not know.

Don’t use a resistor. Do a little more research, spend slightly more, and get an appropriate current or PWM-controlled driver circuit for whatever input voltage you’ll provide. It will be more efficient and you can have multiple output modes, if you’d like.

If you could find a driver that takes 20v input it would be an awesome project to 3D print a DeWalt (or another brand) battery connector / housing and essentially make your own complete flashlight.

I’d probably wire these up for USB (5v) power. That way you have plenty of options. You could run a bunch off a good USB wall-plug, or off a portable power bank… Or off a regular 18V battery with one of those USB adapters.

This looks to be an intriguing possibility. I however, have been wanting to convert a floor lamp, which I love the design of, to LED. But I don’t want to simply install an LED bulb and one reason is that this lamp has a 3-way switch. What I really want to do is replace the lamp socket and switch with an LED chip or chips mounted to a pcb along with a touch switch. The floor lamp is the type that points to the ceiling and with the right LED setup I should be able to do this. It may need a diffuser plate set above the LED. Does anyone know of a good source of materials to accomplish this?

If you search Aliexpress or ebay for “cc/cv DC-DC power supply” you will find many that would work for wide range DC input one watt led driver. There are also smaller and less expensive ones that are used inside many MR11,MR16 LED replacement bulbs but they are not very flexible. Amazon has them as well but typ. 5X the price.

Yep, Ali express has a bunch, and so does flea-bay. Alltronics has an adjustable switching supply for under $8 . Although not consonant current, you can use a low value resistor in series and adjust the voltage out close enough to get you what you need to run off a 20V battery.

If you do go the LM317 route, just keep in mind that the more LEDs you add in series and closer you get to the battery voltage ( allowing for some regulator headroom), the more efficiency you get, otherwise, you’ll get a lot of energy dissipated across the linear regulator as heat. You probably already know this but I’d thought Id mention it.

Also, LED lights need to be driven with constant current for consistant light output, otherwise the light will continue to dim and color will shift as the battery voltage drops if using a simple resistor circuit.

You can use a 555 timer as PWM driver and pass thru transistor as well or even a transistor oscillator, but anymore for the cost, using one of the dedicated ICs and and handful pf parts is just as cheap. The only issue is most new ICs are surface mount. I personally try to stick with SOT-23 or SO-8 packages as they are still manageable if I need to tack them on a proto-board.

For the more DIY die hard, companies like TI, Linear tech, etc have online power design tools that help out with part selection and design simulation. I was just using some last week for a new design. If you have the time, you can create switcher regulators for this purpose for around $2-3 each.

One of the simplest ICs to use is Diodes Inc. AL8861 (it only needs one each external diode, capacitor and resistor)

I was able to squeeze a point-to-point soldered Zetex ZXLD1350 (alternate is ZXLD1356) into the battery case of an LED book reading-light and transformed it from a plain battery driven LED to a high efficiency light, thus tripling the battery life. The circuit is simple enough you can cut traces into a PCB using X-acto knife. There are many more examples out there.

I considered that, inspired by the Ego I’ve been testing that has built-in lights (that eventually get covered in snow), although modifying cheap flashlights might be easier. Even if fabricating a weatherproof mount was easy, the modules are not weather sealed.

Could you make one of these run off of a 12V car battery and put a few things together to make a worklight you can leave in your engine bay of your car or truck? I remeber seeing some old trucks had a worklight on a spool that stayed in the engine bay and readily available. Maybe attach a magnet to a swiveling base. Could be a fun little project.

Best thing I ever did too my dewalt light that used the same led and lens was to glue some dotted translucent Ikea drawer liner I cut in a circle to fit. Diffises the light nicely without distorting the beam too much.

They have a lot of tools there and lets just say that not everything was stock OEM. Two things that I remember are that some of the Bosch Dual Glide miter saws (both 10 and 12″) were modified with a different motor and that on a “junk” or rather “Christmas sales” table were some of the DeWalt flashlights that belong with those heads missing. Instead, they had a standard threaded light bulb socket wired into its place. I found where your lights came from.